1. Field of the Invention
The invention relates to a trolley for a folding door. A plurality of trolleys attached to the top of the folding door are used to suspend the door from an overhead track. The trolleys roll along the track and help the door to easily fold or unfold as required. The invention is also directed toward a folding door incorporating the trolleys.
2. Description of the Related Art
The prior art trolleys usually have a single wheel rotatably mounted on an axle. The axle is fixed to the top of a mounting post on the door, and extends from the post laterally relative to the direction the trolley travels. When the trolley is fixedly mounted on the top of a folding door, via the mounting post, the trolley wheel, offset to the side from the post, sits on an overhead track supporting the folding door off the ground. The door can often swing laterally to the side from the vertical plane it normally rests in while being opened or closed. Since the wheel axle is fixedly mounted to the trolley assembly and the trolley assembly is fixedly mounted to the door, if the door does swing laterally, the wheel will tilt and rub against a side of the track creating friction. The rubbing makes it harder to open or close the door and adds wear to the wheel. The door can also swing laterally while being moved around a curved section of track, centrifugal force swinging the door outwardly of the curve and tilting the trolley wheels on the curve inwardly to bear against the track, again making it harder to move the door.